STM32L151xx STM32L152xx

Transcription

1 STM32L151xx STM32L152xx Ultralow power ARM-based 32-bit MCU with up to 128 KB Flash, RTC, LCD, USB, USART, I2C, SPI, timers, ADC, DAC, comparators Features Preliminary data Operating conditions Operating power supply range: 1.65 V to 3.6 V (without BOR) or 1.8 V to 3.6 V (with BOR option) Temperature range: 40 to 85 C Low power features 4 modes: Sleep, Low-power run (15 µa at 32 khz), Low-power sleep (4 µa), Stop with RTC (1.2 µa), Stop (0.5 µa), Standby (0.27 µa) Dynamic core voltage scaling down to 233 µa/mhz Ultralow leakage per I/O: 50 na Fast wakeup from Stop: 8 µs Three wakeup pins Core: ARM 32-bit Cortex -M3 CPU 32 MHz maximum frequency, 33.3 DMIPS peak (Dhrystone 2.1) Memory protection unit Reset and supply management Low power, ultrasafe BOR (brownout reset) with 5 selectable thresholds Ultralow power POR/PDR Programmable voltage detector (PVD) Clock management 1 to 24 MHz crystal oscillator 32 khz oscillator for RTC with calibration Internal 16 MHz factory-trimmed RC Internal 37 khz low consumption RC Internal multispeed low power RC, 64 khz to 4 MHz with a consumption down to 1.5 µa PLL for CPU clock and USB (48 MHz) Low power calendar RTC Alarm, periodic wakeup from Stop/Standby Memories Up to 128 Kbyte of Flash memory with ECC LQFP mm LQFP mm LQFP mm 4 Kbyte of data EEPROM with ECC Up to 16 Kbyte of RAM Up to 83 fast I/Os (73 of which are 5 V-tolerant) all mappable on 16 external interrupt vectors Development support Serial wire debug, JTAG and trace DMA: 7-channel DMA controller, supporting timers, ADC, SPIs, I 2 Cs and USARTs LCD 8 40 or 4 44 with step-up converter 12-bit ADC up to 1 Msps/24 channels Temperature sensor and internal voltage reference Operates down to 1.8 V 2 12-bit DACs with output buffers 2 ultralow power comparators Window mode and wakeup capability 10 timers: 6 16-bit general-purpose timers, each with up to 4 IC/OC/PWM channels 2 16-bit basic timers 2 watchdog timers (independent and window) Up to 8 communication interfaces Up to 2 I 2 C interfaces (SMBus/PMBus) Up to 3 USARTs (ISO 7816 interface, LIN, IrDA capability, modem control) Up to 2 SPIs (16 Mbit/s) USB 2.0 full-speed interface CRC calculation unit, 96-bit unique ID Table 1. Reference STM32L151xx STM32L152xx BGA mm BGA mm Device summary Part number VFQFPN mm STM32L151CB, STM32L151RB, STM32L151VB, STM32L151C8, STM32L151R8, STM32L151V8 STM32L152CB, STM32L152RB, STM32L152VB, STM32L152C8, STM32L152R8, STM32L152V8 July 2010 Doc ID Rev 1 1/106 This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice. 1

2 Contents STM32L151xx, STM32L152xx Contents 1 Introduction Description Device overview Ultralow power device continuum Performance Shared peripherals Common system strategy Features Functional overview Low power modes ARM Cortex -M3 core with MPU Reset and supply management Power supply schemes Power supply supervisor Voltage regulator Boot modes Clock management Low power real-time clock and backup registers GPIOs (general-purpose inputs/outputs) Memories DMA (direct memory access) LCD (liquid crystal display) ADC (analog-to-digital converter) DAC (digital-to-analog converter) Ultralow power comparators and reference voltage Routing interface Timers and watchdogs General-purpose timers (TIM2, TIM3, TIM4, TIM9, TIM10 and TIM11) Basic timers (TIM6 and TIM7) SysTick timer Independent watchdog (IWDG) /106 Doc ID Rev 1

3 STM32L151xx, STM32L152xx Contents Window watchdog (WWDG) Communication interfaces I²C bus Universal synchronous/asynchronous receiver transmitter (USART) Serial peripheral interface (SPI) Universal serial bus (USB) CRC (cyclic redundancy check) calculation unit Development support Pin descriptions Memory mapping Electrical characteristics Parameter conditions Minimum and maximum values Typical values Typical curves Loading capacitor Pin input voltage Power supply scheme Current consumption measurement Absolute maximum ratings Operating conditions General operating conditions Embedded reset and power control block characteristics Embedded internal reference voltage Supply current characteristics External clock source characteristics Internal clock source characteristics PLL characteristics Memory characteristics EMC characteristics Absolute maximum ratings (electrical sensitivity) I/O port characteristics NRST pin characteristics TIM timer characteristics Doc ID Rev 1 3/106

4 Contents STM32L151xx, STM32L152xx Communications interfaces bit ADC characteristics DAC electrical specifications Temperature sensor characteristics Comparator LCD controller (STM32L152xx only) Package characteristics Package mechanical data Thermal characteristics Reference document Selecting the product temperature range Ordering information scheme Revision history /106 Doc ID Rev 1

5 STM32L151xx, STM32L152xx List of tables List of tables Table 1. Device summary Table 2. Ultralow power STM32L15xxx device features and peripheral counts Table 3. Timer feature comparison Table 4. STM32L15xxx pin definitions Table 5. Alternate function input/output Table 6. Voltage characteristics Table 7. Current characteristics Table 8. Thermal characteristics Table 9. General operating conditions Table 10. Functionalities depending on the operating power supply range Table 11. Embedded reset and power control block characteristics Table 12. Embedded internal reference voltage Table 13. Current consumption in Run mode, code with data processing running from Flash Table 14. Current consumption in Run mode, code with data processing running from RAM Table 15. Current consumption in Sleep mode Table 16. Current consumption in Low power run mode Table 17. Current consumption in Low power sleep mode Table 18. Typical and maximum current consumptions in Stop mode Table 19. Typical and maximum current consumptions in Standby mode Table 20. Typical and maximum timings in Low power modes Table 21. Peripheral current consumption Table 22. High-speed external user clock characteristics Table 23. Low-speed external user clock characteristics Table 24. HSE 1-24 MHz oscillator characteristics Table 25. LSE oscillator characteristics (f LSE = khz) Table 26. HSI oscillator characteristics Table 27. LSI oscillator characteristics Table 28. MSI oscillator characteristics Table 29. PLL characteristics Table 30. RAM and hardware registers Table 31. Flash memory characteristics Table 32. Flash memory endurance and data retention Table 33. EMS characteristics Table 34. EMI characteristics Table 35. ESD absolute maximum ratings Table 36. Electrical sensitivities Table 37. I/O static characteristics Table 38. Output voltage characteristics Table 39. I/O AC characteristics Table 40. NRST pin characteristics Table 41. TIMx characteristics Table 42. I 2 C characteristics Table 43. SCL frequency (f PCLK1 = 36 MHz, V DD = 3.3 V) Table 44. SPI characteristics Table 45. USB startup time Table 46. USB DC electrical characteristics Table 47. USB: full-speed electrical characteristics Table 48. ADC characteristics Doc ID Rev 1 5/106

6 List of tables STM32L151xx, STM32L152xx Table 49. ADC accuracy - limited test conditions Table 50. ADC accuracy Table 51. DAC characteristics Table 52. TS characteristics Table 53. Comparator 1 characteristics Table 54. Comparator 2 characteristics Table 55. LCD controller characteristics Table 56. VFQFPN48 very thin fine pitch quad flat pack nolead 7 7 mm, 0.5 mm pitch package mechanical data Table 57. TFBGA64-8 x 8 active ball array, 5 x 5 mm, 0.5 mm pitch, package mechanical data Table 58. UFBGA100 - ultra fine pitch ball grid array, 7 x 7 mm, 0.50 mm pitch, package mechanical data Table 59. LQPF100, 14 x 14 mm, 100-pin low-profile quad flat package mechanical data Table 60. LQFP64, 10 x 10 mm, 64-pin low-profile quad flat package mechanical data Table 61. LQFP48, 7 x 7 mm, 48-pin low-profile quad flat package mechanical data Table 62. Thermal characteristics Table 63. Ordering information scheme /106 Doc ID Rev 1

7 STM32L151xx, STM32L152xx List of figures List of figures Figure 1. Ultralow power STM32L15xxx block diagram Figure 2. Clock tree Figure 3. STM32L15xxx UFBGA100 ballout Figure 4. STM32L15xxx TFBGA64 ballout Figure 5. STM32L15xxx LQFP100 pinout Figure 6. STM32L15xxx LQFP64 pinout Figure 7. STM32L15xxx LQFP48 pinout Figure 8. STM32L15xxx VFQFPN48 pinout Figure 9. Memory map Figure 10. Pin loading conditions Figure 11. Pin input voltage Figure 12. Power supply scheme Figure 13. Current consumption measurement scheme Figure 10. Power supply thresholds Figure 14. High-speed external clock source AC timing diagram Figure 15. Low-speed external clock source AC timing diagram Figure 16. HSE oscillator circuit diagram Figure 17. Typical application with a khz crystal Figure 18. I/O AC characteristics definition Figure 19. Recommended NRST pin protection Figure 20. I 2 C bus AC waveforms and measurement circuit Figure 21. SPI timing diagram - slave mode and CPHA = Figure 22. SPI timing diagram - slave mode and CPHA = 1 (1) Figure 23. SPI timing diagram - master mode (1) Figure 24. USB timings: definition of data signal rise and fall time Figure 25. ADC accuracy characteristics Figure 26. Typical connection diagram using the ADC Figure 27. Power supply and reference decoupling (V REF+ not connected to V DDA ) Figure 28. Power supply and reference decoupling (V REF+ connected to V DDA ) Figure bit buffered /non-buffered DAC Figure 30. VFQFPN48 7 x 7 mm, 0.5 mm pitch, package outline Figure 31. (1) Recommended footprint (dimensions in mm) Figure 32. Recommended PCB design rules for pads (0.5 mm pitch BGA) Figure 33. TFBGA64-8 x 8 active ball array, 5 x 5 mm, 0.5 mm pitch, package outline Figure 34. UFBGA100 - ultra fine pitch ball grid array, 7 x 7 mm, 0.50 mm pitch, package outline Figure 35. LQFP100, 14 x 14 mm, 100-pin low-profile quad flat package outline Figure 36. Recommended footprint (1) Figure 37. LQFP64, 10 x 10 mm, 64-pin low-profile quad flat package outline Figure 38. Recommended footprint (1) Figure 39. LQFP48, 7 x 7 mm, 48-pin low-profile quad flat package outline Figure 40. Recommended footprint (1) Figure 41. LQFP100 P D max vs. T A Doc ID Rev 1 7/106

8 Introduction STM32L151xx, STM32L152xx 1 Introduction This datasheet provides the ordering information and mechanical device characteristics of the STM32L151xx and STM32L152xx ultralow power ARM Cortex -based microcontrollers product line. The ultralow power STM32L15xxx family includes devices in 3 different package types: from 48 pins to 100 pins. Depending on the device chosen, different sets of peripherals are included, the description below gives an overview of the complete range of peripherals proposed in this family. These features make the ultralow power STM32L15xxx microcontroller family suitable for a wide range of applications: Medical and handheld equipment Application control and user interface PC peripherals, gaming, GPS and sport equipment Alarm systems, Wired and wireless sensors, Video intercom Utility metering For information on the Cortex -M3 core please refer to the Cortex -M3 Technical Reference Manual, available from the website at the following address: Figure 1 shows the general block diagram of the device family. 8/106 Doc ID Rev 1

9 STM32L151xx, STM32L152xx Description 2 Description The ultralow power STM32L15xxx incorporates the connectivity power of the universal serial bus (USB) with the high-performance ARM Cortex -M3 32-bit RISC core operating at a 32 MHz frequency, a memory protection unit (MPU), high-speed embedded memories (Flash memory up to 128 Kbytes and RAM up to 16 Kbytes), and an extensive range of enhanced I/Os and peripherals connected to two APB buses. All devices offer a 12-bit ADC, 2 DACs and 2 ultralow power comparators, six general-purpose 16-bit timers and two basic timers, which can be used as time bases. Moreover, the STM32L15xxx devices contain standard and advanced communication interfaces: up to two I 2 Cs and SPIs, three USARTs and a USB. They also include a real-time clock and a set of backup registers that remain powered in Standby mode. Finally, the integrated LCD controller has a built-in LCD voltage generator that allows you to drive up to 8 multiplexed LCDs with contrast independent of the supply voltage. The ultralow power STM32L15xxx operates from a 1.8 to 3.6 V power supply (down to 1.65 V at power down) with BOR and from a 1.65 to 3.6 V power supply without BOR option. It is available in the -40 to +85 C temperature range. A comprehensive set of power-saving modes allows the design of low-power applications Doc ID Rev 1 9/106

10 Description STM32L151xx, STM32L152xx 2.1 Device overview Table 2. Ultralow power STM32L15xxx device features and peripheral counts Peripheral STM32L15xCx STM32L15xRx STM32L15xVx Flash - Kbytes RAM - Kbytes Timers General-purpose Basic SPI Communication interfaces I 2 C USART USB GPIOs bit synchronized ADC Number of channels 1 16 channels 1 20 channels 1 24 channels 12-bit DAC Number of channels LCD (STM32L152xx Only) COM x SEG 4x16 4x32 8x28 4x44 8x40 Comparator CPU frequency Operating voltage Operating temperatures Packages 32 MHz 1.8 V to 3.6 V (down to 1.65 V at power-down) with BOR option 1.65 V to 3.6 V (down to 1.65 V at power-down) without BOR option Ambient temperatures: 40 to +85 C Junction temperature: 40 to C LQFP48, VFQFN48 LQFP64, BGA64 LQFP100, BGA /106 Doc ID Rev 1

11 STM32L151xx, STM32L152xx Description 2.2 Ultralow power device continuum The ultralow power STM32L151xx and STM32L152xx are fully pin-to-pin, software and feature compatible. Besides the full compatibility within the family, the devices are part of STMicroelectronics microcontrollers ultralow power strategy which also includes STM8L101xx and STM8L15xx devices. The STM8L and STM32L families allow a continuum of performance, peripherals, system architecture and features. They are all based on STMicroelectronics 0.13 µm ultralow leakage process. Note: The ultralow power STM32L and general-purpose STM32Fxxxx families are pin-to-pin compatible. The STM8L15xxx devices are pin-to-pin compatible with the STM8L101xx devices. Please refer to the STM32F and STM8L documentation for more information on these devices Performance All families incorporate highly energy-efficient cores with both Harvard architecture and pipelined execution: advanced STM8 core for STM8L families and ARM Cortex -M3 core for STM32L family. In addition specific care for the design architecture has been taken to optimize the ma/dmips and ma/mhz ratios. This allows the ultralow power performance to range from 5 up to 33.3 DMIPs Shared peripherals STM8L15xxx and STM32L15xxx share identical peripherals which ensure a very easy migration from one family to another: Analog peripherals: ADC, DAC, and comparators Digital peripherals: RTC and some communication interfaces Common system strategy To offer flexibility and optimize performance, the STM8L15xx and STM32L15xx families use a common architecture: Same power supply range from 1.65 V to 3.6 V, (1.65 V at power down only for STM8L15xx devices) Architecture optimized to reach ultralow consumption both in low power modes and Run mode Fast startup strategy from low power modes Flexible system clock Ultrasafe reset: same reset strategy including power-on reset, power-down reset, brownout reset and programmable voltage detector Features ST ultralow power continuum also lies in feature compatibility: More than 10 packages with pin count from 20 to 100 pins and size down to 3 x 3 mm Memory density ranging from 4 to 128 Kbytes Doc ID Rev 1 11/106

12 Functional overview STM32L151xx, STM32L152xx 3 Functional overview Figure 1 shows the block diagrams. Figure 1. Ultralow power STM32L15xxx block diagram 1. T A = 40 C to +105 C (junction temperature up to 125 C). 2. AF = alternate function on I/O port pin. 12/106 Doc ID Rev 1

13 STM32L151xx, STM32L152xx Functional overview 3.1 Low power modes The ultralow power STM32L15xxx supports dynamic voltage scaling to optimize its power consumption in run mode. The voltage from the internal low-drop regulator that supplies the logic can be adjusted according to the system s maximum operating frequency and the external voltage supply. When executing from Flash memory, the consumptions are: In range 1 (V DD range limited to V), with the CPU running at up to 32 MHz, the consumption is: 290 µa/mhz In range 2 (full V DD range), with a maximum CPU frequency of 16 MHz, the consumption is: 235 µa/mhz In range 3 (full V DD range), with a maximum CPU frequency limited to 4 MHz (generated only with the multispeed internal RC oscillator clock source), the consumption is: 200 µa/mhz. Seven low power modes are provided to achieve the best compromise between low power consumption, short startup time and available wakeup sources: Sleep mode In Sleep mode, only the CPU is stopped. All peripherals continue to operate and can wake up the CPU when an interrupt/event occurs. The Sleep mode power consumption at 16 MHz is of about 1 ma with all peripherals off. Low power run mode This mode is achieved with the multispeed internal (MSI) RC oscillator set to the minimum clock (64 khz), execution from SRAM or Flash memory, and internal regulator in low power mode to minimize the regulator's operating current. In the Low power run mode, the clock frequency and the number of enabled peripherals are both limited. The Low power run mode consumption can be as low as 10.5 µa when executing code from RAM at 32 khz. Low power sleep mode This mode is achieved by entering the Sleep mode with the internal voltage regulator in Low power mode to minimize the regulator s operating current. In the Low power sleep mode, both the clock frequency and the number of enabled peripherals are limited; a typical example would be to have a timer running at 32 khz. When wakeup is triggered by an event or an interrupt, the system reverts to the run mode with the regulator on. The Low power sleep mode consumption is as low as 4 µa when no peripheral is enabled. It is of 5 µa with one timer operating at 32 khz. Stop mode (with or without RTC) The Stop mode achieves the lowest power consumption while retaining the RAM and register contents. All clocks in the V CORE domain are stopped, the PLL, MSI RC, HSI RC and HSE crystal oscillators are disabled. The voltage regulator is in the low power mode. The device can be woken up from the Stop mode by any of the EXTI line, in 8 µs. The EXTI line source can be one of the 16 external lines, the PVD output, the RTC alarm(s), the USB wakeup, the RTC tamper event, the RTC timestamp event, the RTC Wakeup, the Comparator 1 event or Comparator 2 event. The Stop mode consumption with the RTC on the LSE is of 1.3 µa (at 1.8 V) and 1.6 µa (at 3.0 V). The Stop mode consumption without the RTC is of 0.5 µa. Standby mode (with or without RTC) The Standby mode is used to achieve the lowest power consumption. The internal voltage regulator is switched off so that the entire V CORE domain is powered off. The Doc ID Rev 1 13/106

14 Functional overview STM32L151xx, STM32L152xx Note: PLL, MSI RC, HSI RC and HSE crystal oscillators are also switched off. After entering Standby mode, the RAM and register contents are lost except for registers in the Standby circuitry (wakeup logic, IWDG, RTC, LSI, LSE Crystal 32K osc, RCC CSR). The device exits the Standby mode in 60 µs when an external reset (NRST pin), an IWDG reset, a rising edge on one of the three WKUP pins, RTC alarm (Alarm A or Alarm B), RTC tamper event, RTC timestamp event or RTC Wakeup event. The Standby mode consumption is of 1µA (at 1.8 V) and 1.3 µa (at 3.0 V) with the RTC on, and of 270 na with the RTC off. The RTC, the IWDG, and the corresponding clock sources are not stopped by entering the Stop or Standby mode. 3.2 ARM Cortex -M3 core with MPU The ARM Cortex -M3 processor is the latest generation of ARM processors for embedded systems. It has been developed to provide a low-cost platform that meets the needs of MCU implementation, with a reduced pin count and low-power consumption, while delivering outstanding computational performance and an advanced system response to interrupts. The ARM Cortex -M3 32-bit RISC processor features exceptional code-efficiency, delivering the high-performance expected from an ARM core in the memory size usually associated with 8- and 16-bit devices. The memory protection unit (MPU) improves system reliability by defining the memory attributes (such as read/write access permissions) for different memory regions. It provides up to eight different regions and an optional predefined background region. Owing to its embedded ARM core, the STM32L15xxx is compatible with all ARM tools and software. Nested vectored interrupt controller (NVIC) The ultralow power STM32L15xxx embeds a nested vectored interrupt controller able to handle up to 45 maskable interrupt channels (not including the 16 interrupt lines of Cortex -M3) and 16 priority levels. Closely coupled NVIC gives low-latency interrupt processing Interrupt entry vector table address passed directly to the core Closely coupled NVIC core interface Allows early processing of interrupts Processing of late arriving, higher-priority interrupts Support for tail-chaining Processor state automatically saved Interrupt entry restored on interrupt exit with no instruction overhead This hardware block provides flexible interrupt management features with minimal interrupt latency. 14/106 Doc ID Rev 1

15 STM32L151xx, STM32L152xx Functional overview 3.3 Reset and supply management Power supply schemes V DD = 1.65 to 3.6 V: external power supply for I/Os and the internal regulator. Provided externally through V DD pins. V SSA, V DDA = 1.65 to 3.6 V: external analog power supplies for ADC, reset blocks, RCs and PLL (minimum voltage to be applied to V DDA is 1.8 V when the ADC is used). V DDA and V SSA must be connected to V DD and V SS, respectively Power supply supervisor The device has an integrated ZEROPOWER power-on reset (POR)/power-down reset (PDR) that can be coupled with a brownout reset (BOR) circuitry. For devices operating between 1.8 and 3.6 V, the BOR is always active at power-on and ensures proper operation starting from 1.8 V. After the 1.8 V BOR threshold is reached, the option byte loading process starts, either to confirm or modify default thresholds, or to disable BOR permanently (in which case, the V DD min value at power down is 1.65 V). Five BOR thresholds are available through option bytes, starting from 1.8 V to 3 V. To reduce the power consumption in Stop mode, it is possible to automatically switch off the internal reference voltage (V REFINT ) in Stop mode. The device remains in reset mode when V DD is below a specified threshold, V POR/PDR or V BOR, without the need for any external reset circuit. Note: The start-up time at power-on is typically 3.3 ms. For devices operating between 1.65 V and 3.6 V, the BOR is permanently disabled. Consequently, the start-up time at power-on can be decreased down to 1ms typically. The device features an embedded programmable voltage detector (PVD) that monitors the V DD /V DDA power supply and compares it to the V PVD threshold. This PVD offers 7 different levels between 1.85 V and 3.05 V, chosen by software, with a step around 200 mv. An interrupt can be generated when V DD /V DDA drops below the V PVD threshold and/or when V DD /V DDA is higher than the V PVD threshold. The interrupt service routine can then generate a warning message and/or put the MCU into a safe state. The PVD is enabled by software Voltage regulator The regulator has three operation modes: main (MR), low power (LPR) and power down. MR is used in Run mode (nominal regulation) LPR is used in the Low-power run, Low-power sleep and Stop modes Power down is used in Standby mode: the regulator output is high impedance: the kernel circuitry is powered down, inducing zero consumption (but the contents of the registers and RAM are lost are lost except for the standby circuitry (wakeup logic, IWDG, RTC, LSI, LSE crystal 32K osc, RCC CSR) Boot modes At startup, boot pins are used to select one of three boot options: Boot from Flash memory Boot from System Memory Boot from embedded RAM Doc ID Rev 1 15/106

16 Functional overview STM32L151xx, STM32L152xx The boot loader is located in System Memory. It is used to reprogram the Flash memory by using USART1 or USART2. For further details please refer to AN Clock management The clock controller distributes the clocks coming from different oscillators to the core and the peripherals. It also manages clock gating for low power modes and ensures clock robustness. It features: Clock prescaler: to get the best tradeoff between speed and current consumption, the clock frequency to the CPU and peripherals can be adjusted by a programmable prescaler Safe clock switching: clock sources can be changed safely on the fly in run mode through a configuration register. Clock management: to reduce power consumption, the clock controller can stop the clock to the core, individual peripherals or memory. Master clock source: three different clock sources can be used to drive the master clock: 1-24 MHz high-speed external crystal (HSE), that can supply a PLL 16 MHz high-speed internal RC oscillator (HSI), trimmable by software, that can supply a PLL Multispeed internal RC oscillator (MSI), trimmable by software, able to generate 7 frequencies (64 khz, 128 khz, 256 khz, 512 khz, 1.02 MHz, 2.05 MHz, 4.1 MHz) with a consumption proportional to speed, down to 750 na typical. When a khz clock source is available in the system (LSE), the MSI frequency can be trimmed by software down to a ±0.5% accuracy. Auxiliary clock source: two ultralow power clock sources that can be used to drive the LCD controller and the real-time clock: khz low-speed external crystal (LSE) 37 khz low-speed internal RC (LSI), also used to drive the independent watchdog. The LSI clock can be measured using the high-speed internal RC oscillator for greater precision. RTC and LCD clock sources: the LSI, LSE or HSE sources can be chosen to clock the RTC and the LCD, whatever the system clock. USB clock source: the embedded PLL has a dedicated 48 MHz clock output to supply the USB interface. Startup clock: after reset, the microcontroller restarts by default with an internal 2 MHz clock (MSI). The prescaler ratio and clock source can be changed by the application program as soon as the code execution starts. Clock security system (CSS): this feature can be enabled by software. If a HSE clock failure occurs, the master clock is automatically switched to HSI and a software interrupt is generated if enabled. Clock-out capability (MCO: microcontroller clock output): it outputs one of the internal clocks for external use by the application. Several prescalers allow the configuration of the AHB frequency, the high-speed APB (APB2) and the low-speed APB (APB1) domains. The maximum frequency of the AHB and the APB domains is 32 MHz. See Figure 2 for details on the clock tree. 16/106 Doc ID Rev 1

17 STM32L151xx, STM32L152xx Functional overview Figure 2. Clock tree 3. For the USB function to be available, both HSE and PLL must be enabled, with the CPU running at either 24 MHz or 32 MHz. 3.5 Low power real-time clock and backup registers The real-time clock (RTC) is an independent BCD timer/counter. Dedicated registers contain the second, minute, hour (12/24 hour), week day, date, month, year, in BCD (binary-coded decimal) format. Correction for 28, 29 (leap year), 30, and 31 day of the month are made Doc ID Rev 1 17/106

18 Functional overview STM32L151xx, STM32L152xx automatically. The RTC provides a programmable alarm and programmable periodic interrupts with wakeup from Stop and Standby modes. The programmable wakeup time ranges from 120 µs to 36 hours Stop mode consumption with LSI and Auto-wakeup: 1.2 µa (at 1.8 V) and 1.4 µa (at 3.0 V) Stop mode consumption with LSE, calendar and Auto-wakeup: 1.3 µa (at 1.8V), 1.6 µa (at 3.0 V) The RTC can be calibrated with an external 512 Hz output, and a digital compensation circuit helps reduce drift due to crystal deviation. There are twenty 32-bit backup registers provided to store 80 bytes of user application data. They are cleared in case of tamper detection. 3.6 GPIOs (general-purpose inputs/outputs) Each of the GPIO pins can be configured by software as output (push-pull or open-drain), as input (with or without pull-up or pull-down) or as peripheral alternate function. Most of the GPIO pins are shared with digital or analog alternate functions, and can be individually remapped using dedicated AFIO registers. All GPIOs are high-current-capable except for analog pins. The alternate function configuration of I/Os can be locked if needed following a specific sequence in order to avoid spurious writing to the I/O registers. The I/O controller is connected to the AHB with a toggling speed of up to 16 MHz. External interrupt/event controller (EXTI) The external interrupt/event controller consists of 23 edge detector lines used to generate interrupt/event requests. Each line can be individually configured to select the trigger event (rising edge, falling edge, both) and can be masked independently. A pending register maintains the status of the interrupt requests. The EXTI can detect an external line with a pulse width shorter than the Internal APB2 clock period. Up to 83 GPIOs can be connected to the 16 external interrupt lines. 18/106 Doc ID Rev 1

19 STM32L151xx, STM32L152xx Functional overview 3.7 Memories The STM32L15xxx devices have the following features: Up to 16 Kbyte of embedded RAM accessed (read/write) at CPU clock speed with 0 wait states. With the enhanced bus matrix, operating the RAM does not lead to any performance penalty during accesses to the system bus (AHB and APB buses). The non-volatile memory is divided into three arrays: 64 or 128 Kbyte of embedded Flash program memory 4 Kbyte of data EEPROM Options bytes The options bytes are used to write-protect the memory (with 4 KB granularity) and/or readout-protect the whole memory with the following options: Level 0: no readout protection Level 1: memory readout protection, the Flash memory cannot be read from or written to if either debug features are connected or boot in RAM is selected Level 2: chip readout protection, debug features (Cortex-M3 JTAG and serial wire) and boot in RAM selection disabled (JTAG fuse) The whole non-volatile memory embeds the error correction code (ECC) feature. 3.8 DMA (direct memory access) The flexible 7-channel, general-purpose DMA is able to manage memory-to-memory, peripheral-to-memory and memory-to-peripheral transfers. The DMA controller supports circular buffer management, avoiding the generation of interrupts when the controller reaches the end of the buffer. Each channel is connected to dedicated hardware DMA requests, with software trigger support for each channel. Configuration is done by software and transfer sizes between source and destination are independent. The DMA can be used with the main peripherals: SPI, I 2 C, USART, general-purpose timers and ADC. 3.9 LCD (liquid crystal display) The LCD drives up to 8 common terminals and 44 segment terminals to drive up to 320 pixels. Internal step-up converter to guarantee functionality and contrast control irrespective of V DD. This converter can be deactivated, in which case the V LCD pin is used to provide the voltage to the LCD Supports static, 1/2, 1/3, 1/4 and 1/8 duty Supports static, 1/2, 1/3 and 1/4 bias Phase inversion to reduce power consumption and EMI Up to 8 pixels can be programmed to blink Unneeded segments and common pins can be used as general I/O pins LCD RAM can be updated at any time owing to a double-buffer The LCD controller can operate in Stop mode Doc ID Rev 1 19/106

20 Functional overview STM32L151xx, STM32L152xx 3.10 ADC (analog-to-digital converter) A 12-bit analog-to-digital converters is embedded into STM32L15xxx devices with up to 24 external channels, performing conversions in single-shot or scan mode. In scan mode, automatic conversion is performed on a selected group of analog inputs. The ADC can be served by the DMA controller. An analog watchdog feature allows very precise monitoring of the converted voltage of one, some or all selected channels. An interrupt is generated when the converted voltage is outside the programmed thresholds. The events generated by the general-purpose timers (TIMx) can be internally connected to the ADC start trigger and injection trigger, to allow the application to synchronize A/D conversions and timers. The ADC includes a specific low power mode. The converter is able to operate at maximum speed even if the CPU is operating at a very low frequency and has an auto-shutdown function. The ADC s runtime and analog front-end current consumption are thus minimized whatever the MCU operating mode. Temperature sensor The temperature sensor has to generate a voltage that varies linearly with temperature. The conversion range is between 1.8 V < V DDA < 3.6 V. The temperature sensor is internally connected to the ADC_IN16 input channel DAC (digital-to-analog converter) The two 12-bit buffered DAC channels can be used to convert two digital signals into two analog voltage signal outputs. The chosen design structure is composed of integrated resistor strings and an amplifier in non-inverting configuration. This dual digital Interface supports the following features: two DAC converters: one for each output channel up to 10-bit output left or right data alignment in 12-bit mode synchronized update capability noise-wave generation triangular-wave generation dual DAC channels independent or simultaneous conversions DMA capability for each channel (including the underrun interrupt) external triggers for conversion input reference voltage V REF+ Eight DAC trigger inputs are used in the STM32L15xxx. The DAC channels are triggered through the timer update outputs that are also connected to different DMA channels. 20/106 Doc ID Rev 1

21 STM32L151xx, STM32L152xx Functional overview 3.12 Ultralow power comparators and reference voltage The STM32L15xxx embeds two comparators sharing the same current bias and reference voltage. The reference voltage can be internal or external (coming from an I/O). one comparator with fixed threshold one comparator with rail-to-rail inputs, fast or slow mode. The threshold can be one of the following: DAC output External I/O Internal reference voltage (V REFINT ) or V REFINT submultiple (1/4, 1/2, 3/4) Both comparators can wake up from Stop mode, and be combined into a window comparator. The internal reference voltage is available externally via a low power / low current output buffer (driving current capability of 1 µa typical) Routing interface This interface controls the internal routing of I/Os to TIM2, TIM3, TIM4 and to the comparator and reference voltage output Timers and watchdogs The ultralow power STM32L15xxx devices include six general-purpose timers, two basic timers and two watchdog timers. Table 3 compares the features of the general-purpose and basic timers. Table 3. Timer feature comparison Timer Counter resolution Counter type Prescaler factor DMA request generation Capture/compare channels Complementary outputs TIM2, TIM3, TIM4 16-bit Up, down, up/down Any integer between 1 and Yes 4 No TIM9 16-bit Up Any integer between 1 and No 2 No TIM10, TIM11 16-bit Up Any integer between 1 and No 1 No TIM6, TIM7 16-bit Up Any integer between 1 and Yes 0 No General-purpose timers (TIM2, TIM3, TIM4, TIM9, TIM10 and TIM11) There are six synchronizable general-purpose timers embedded in the STM32L15xxx devices (see Table 3 for differences). Doc ID Rev 1 21/106

22 Functional overview STM32L151xx, STM32L152xx TIM2, TIM3, TIM4 These timers are based on a 16-bit auto-reload up/downcounter and a 16-bit prescaler. They feature 4 independent channels each for input capture/output compare, PWM or onepulse mode output. This gives up to 12 input captures/output compares/pwms on the largest packages. The TIM2, TIM3, TIM4 general-purpose timers can work together or with the TIM10, TIM11 and TIM9 general-purpose timers via the Timer Link feature for synchronization or event chaining. Their counter can be frozen in debug mode. Any of the general-purpose timers can be used to generate PWM outputs. TIM2, TIM3, TIM4 all have independent DMA request generation. These timers are capable of handling quadrature (incremental) encoder signals and the digital outputs from 1 to 3 hall-effect sensors. TIM10, TIM11 and TIM9 These timers are based on a 16-bit auto-reload upcounter and a 16-bit prescaler. TIM10 and TIM11 feature one independent channel, whereas TIM9 has two independent channels for input capture/output compare, PWM or one-pulse mode output. They can be synchronized with the TIM2, TIM3, TIM4 full-featured general-purpose timers. They can also be used as simple time bases and be clocked by the LSE clock source ( khz) to provide time bases independent from the main CPU clock Basic timers (TIM6 and TIM7) These timers are mainly used for DAC trigger generation. They can also be used as generic 16-bit time bases SysTick timer This timer is dedicated to the OS, but could also be used as a standard downcounter. It is based on a 24-bit downcounter with autoreload capability and a programmable clock source. It features a maskable system interrupt generation when the counter reaches Independent watchdog (IWDG) The independent watchdog is based on a 12-bit downcounter and 8-bit prescaler. It is clocked from an independent 37 khz internal RC and, as it operates independently of the main clock, it can operate in Stop and Standby modes. It can be used either as a watchdog to reset the device when a problem occurs, or as a free-running timer for application timeout management. It is hardware- or software-configurable through the option bytes. The counter can be frozen in debug mode Window watchdog (WWDG) The window watchdog is based on a 7-bit downcounter that can be set as free-running. It can be used as a watchdog to reset the device when a problem occurs. It is clocked from the main clock. It has an early warning interrupt capability and the counter can be frozen in debug mode. 22/106 Doc ID Rev 1

23 STM32L151xx, STM32L152xx Functional overview 3.15 Communication interfaces I²C bus Up to two I²C bus interfaces can operate in multimaster and slave modes. They can support standard and fast modes. They support dual slave addressing (7-bit only) and both 7- and 10-bit addressing in master mode. A hardware CRC generation/verification is embedded. They can be served by DMA and they support SM Bus 2.0/PM Bus Universal synchronous/asynchronous receiver transmitter (USART) All USART interfaces are able to communicate at speeds of up to 4 Mbit/s. They provide hardware management of the CTS and RTS signals. They support IrDA SIR ENDEC, are ISO 7816 compliant and have LIN Master/Slave capability. All USART interfaces can be served by the DMA controller Serial peripheral interface (SPI) Up to two SPIs are able to communicate at up to 16 Mbits/s in slave and master modes in full-duplex and simplex communication modes. The 3-bit prescaler gives 8 master mode frequencies and the frame is configurable to 8 bits or 16 bits. The hardware CRC generation/verification supports basic SD Card/MMC modes. Both SPIs can be served by the DMA controller Universal serial bus (USB) The STM32L15xxx embeds a USB device peripheral compatible with the USB full-speed 12 Mbit/s. The USB interface implements a full-speed (12 Mbit/s) function interface. It has software-configurable endpoint setting and supports suspend/resume. The dedicated 48 MHz clock is generated from the internal main PLL (the clock source must use a HSE crystal oscillator) CRC (cyclic redundancy check) calculation unit The CRC (cyclic redundancy check) calculation unit is used to get a CRC code from a 32-bit data word and a fixed generator polynomial. Among other applications, CRC-based techniques are used to verify data transmission or storage integrity. In the scope of the EN/IEC standard, they offer a means of verifying the Flash memory integrity. The CRC calculation unit helps compute a signature of the software during runtime, to be compared with a reference signature generated at linktime and stored at a given memory location. Doc ID Rev 1 23/106

24 Functional overview STM32L151xx, STM32L152xx 3.17 Development support Serial wire JTAG debug port (SWJ-DP) The ARM SWJ-DP interface is embedded, and is a combined JTAG and serial wire debug port that enables either a serial wire debug or a JTAG probe to be connected to the target. The JTAG TMS and TCK pins are shared with SWDIO and SWCLK, respectively, and a specific sequence on the TMS pin is used to switch between JTAG-DP and SW-DP. The JTAG port can be permanently disabled with a JTAG fuse. Embedded Trace Macrocell The ARM Embedded Trace Macrocell provides a greater visibility of the instruction and data flow inside the CPU core by streaming compressed data at a very high rate from the STM32L15xxx through a small number of ETM pins to an external hardware trace port analyzer (TPA) device. The TPA is connected to a host computer using USB, Ethernet, or any other high-speed channel. Real-time instruction and data flow activity can be recorded and then formatted for display on the host computer running debugger software. TPA hardware is commercially available from common development tool vendors. It operates with third party debugger software tools. 24/106 Doc ID Rev 1